Chapter 22 builds on its preceding chapter, discussing “security detention,” confinement without criminal charges for security reasons during armed conflicts or other situations of violence. This is presumably the fate of most, if not all, of the forty remaining Guantánamo detainees. The chapter compares security detention with other forms of wartime internment, including World War II Swiss internment of US and German aircrews. Law, LOAC or otherwise, authorizing internment during non-international armed conflicts is sparse but authorities (such as this textbook) point to a 2014 UK case, and the criticism that followed its resolution, as pointing the way to LOAC (Sections III and IV of 1949 Geneva Convention IV) that would allow and control security detention. Much of the chapter describes present-day US security detention policy. A difficulty is squaring LOAC with security detention beyond the conclusion of hostilities. Surprisingly, however, the US Supreme Court has a lon, if not unanimous, record of approving security detention well past the end of hostilities. Those cases suggest that current Guantánamo detainees are probably going to age and die in place.

This chapter examines settlement practice on detention in light of international humanitarian law and human rights law. Section 2 identifies the international legal frameworks that regulate detention, drawing the necessary distinctions between peacetime and armed conflict, and between international and non-international armed conflict, which frame questions on relevant applicable law. Section 3 then examines the specific legal norms relating to prisoners of war and civilian detainees within international armed conflict and their interaction with settlement practice; while Section 4 does the same in relation to legal norms regulating detention in non-international armed conflicts. In the context of peace agreements, the focus is on two interconnected issues which extend into a post bellum phase, as important subject matter for settlement practice: release and repatriation; and transitional justice. By way of conclusion, Section 5 considers whether settlement provisions on detainees reflect a common practice that develops international legal standards.